A semiconductor light emission element such as a semiconductor laser or a light emitting diode has been used as a light source for illumination devices or display devices instead of a lamp whose life time is short. The laser light source whose light emission area is small, whose light output can be easily synthesized, and whose monochromaticity can provide the wide color gamut is considered promising in particular as a high power light source. However, when the laser is used as the light source, a phenomenon specific to the laser appears which looks like glare of flecks called speckle noise.
Hence, in a conventional semiconductor laser light source, the interval of adjacent waveguides arrayed in the central portion of a plurality of waveguides constituting a semiconductor laser array is designed to be narrower than the interval of adjacent waveguides arrayed in end portions (for example, refer to Patent Document 1). Moreover, since another conventional semiconductor laser light source is configured so as to have a stress distribution whose stress is different in the arrayed direction of the laser emission end faces in a semiconductor laser array, the wavelength width of the light emitted from the semiconductor laser light source becomes broad, and therefore speckle noise has been reduced (for example, refer to Patent Document 2).